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The ratio in the ages of A and B, 1 year ago was 3 : 4. While it will be 5 : 6 after 1 year. What is the present age of B ?
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- 8 years
- 4 years
- 6 years
- None of these
Correct Option: D
Let the present age of A and B be x and y years respectively
From 1st condition
(x - 1) / (y -1) = 3/4
⇒ 4x - 4 = 3y - 3
⇒ 4x - 3y = 1 ... (i)
From 2nd condition,
(x + 1) / (y + 1) = 5/6
⇒ 6x + 6 = 5y + 5
⇒ 6x - 5y = -1 ...(ii)
Multiplying equation (i) by 3 and equation (ii) by 2 and subtract
y = 5
∴ Present age of B = 5 years
